What about PowerPoint's AutoSave?
PowerPoint has two types of automatic save features.
In the cloud
If you're logged into your Microsoft account and using Office 365, you'll see an AutoSave option at the top of the PowerPoint window. When this is toggled on (and normally it is, by default), PowerPoint will save your work every so often, automatically.
This is generally A Good Thing. Or even A Very Very Good Thing. Except when you've just accidentally deleted half of your slides and then realize that OMG it AUTOSAVED the ruined version!
OneDrive's versioning will probably save you in that case, but it's not a bad idea to keep periodic backup saves under different file names, just to be extra careful.
Saving on your local hard drive
You don't get this AutoSave feature when you're not storing your files on OneDrive. So then what?
If you've visited PowerPoint's Options dialog, you may have seen a Save option that says something like "Save AutoRecover information every XX minutes" where XX is a box where you can choose a number.
Beneath it are a couple other related options.
Note that it says AutoRECOVER, not AutoSave. It's easy to assume that this is an AutoSave feature, one that will cause PowerPoint to save your work every so often, but that's not what it does.
Instead, it saves crash recovery information periodically. But only IF PowerPoint crashes and IF PowerPoint is smart enough to realize "OH! I'm crashing!"
If all that works, PowerPoint can restart itself and recover your presentation up to the point of the last AutoRecover save. That's a good thing, no question.
But AutoRecover saves to a format all its own, not to a PowerPoint file that you can simply open. If you do something unfortunate by mistake or if a crash is severe enough that PowerPoint can't catch itself, the AutoRecover and its data won't help you.
For example, suppose you've worked on a presentation for three days nonstop. You tell PowerPoint to Quit and mistakenly click NO when it asks if you want to save. Sorry, but that that three days of work is gone. AutoRecover (not AutoSave, remember) won't get it back.
Then how can you protect yourself?
First: Press CTRL+S every so often to save your presentation. Your own human-powered AutoSave feature! If something goes badly sideways, just quit PowerPoint, restart and open your file again to get back to wherever you were at the last CTRL+S save.
Next: Give your files names that include the date.
Whenever you're about to make any substantial changes, do a File | Save As and give the file a new name: MyFile_2030-07-30.PPTX or even MyFile_2030-07-30-001.PPTX if you're making lots of changes on July 30th.
If you'd like something a bit more automatic, try PowerPoint MVP Shyam Pillai's free Sequential Save add-in. Configure it and then just click the Sequential Save button to have it automatically save your presentation under a new sequential name.
Either way, you'll always be able to work backwards to a previous file that was working correctly, no matter what's gone wrong in the current version.